Portable furnace



April 21, 1931. N, MaCDONALD 1,802,146

PORTABLE FURNACE Filed June 16, 1928 INVENTUH.

- Q7ZY7ZCZZM Patented Apr. 21, 1931 5 ALEXANDER N. MACDONALD, or'rononro, ONTARIO, CANADA PORTABLE FURNACE Application filed. June 16,

This invention relates to furnaces employ ing liquid or gaseous fuel and intended for the heating of metals, and my object is to devise a. small portable furnace of this type particularly adapted for the heating of V 2 miners drill bits when the latter require to be sharpened or reforged.

I attainmy object by forming the furnace chamber with a small cross-sectional area relative to its length and by providing it with 13 a burner nozzle in each end discharging towards one another. The burner nozzles are of right-angular construction and are connected with a fuel tank behind the furnace chamber, the tank and chamber being sup- 15 ported on a common base. I

The device is hereinafter more specifically described and is illustrated in the accompanying drawings in which Fig. 1 is a plan view, partly in section, of

.- my'furnace;

Fig. 2 a side elevation of the same;

Fig. 3 a vertical longitudinal section of one of the burners; and

Fig. 1 is a horizontal longitudinal section of the same.

In the drawings like numerals of reference indicate correspondingparts in the different figures.

1 is a base, to which is connected a stand 2,

preferably of metal, and on the upper end of which is supported the furnace chamber which is formed of a casing 3 lined with suitable refractory material forming the top, bottom, ends and front wall of the furnace. This chamber is suitably proportioned to suit the purpose for which the device is intended. It will be noted that the chamber of the furnace is of small cross-sectional area rela tive to its length, the particular showing be ing intended for the reception of three of the ordinary drill bits employed in mining drills. I

Through the front wall of the chamber 18 formed an opening 5, which is relatively long and in front of which is supported a shelf 6 at thelevel of the under side of the opening.

The opening is of less height than the chamber and its lower side is above the bottom of 59 the chamber. Behind the chamber the fuel 1928; serin No. 285,985.

tank 7 is supported on the base 1. 7 This fuel tank is provided with the discharge pipe 8, air pump 9 and filling cap 10, these parts being substantially the same as provided in the ordinary plumbers blow torch; The discharge pipe 8 is provided with the branches ,8 which, by means of suitable elbows, are brought into parallelism with the ends of the furnace. Each branch pipe is connected with a burner body 10 which burner bodies are substantially parallel to the ends of the furnacechamber and are located close thereto. Each burner body is provided with a burner nozzle 11 extending at right angles thereto through the adjacent end of the furnace chamber which is of the flaring formshown. The burner nozzles thus discharge towards one another lengthwise of the chamber. Preferably, however, they are so set that one discharges somewhat above and the other somewhat below the axis of the furnace as I thus secure substantially even heating at all points lengthwise of the furnace chamber. These nozzles, though of ordinary blow torch size, are large relative to the cross sectional area of the furnace chamber, so that the hot blasts therefrom are concentrated along the axis of the furnace in which the drill bits to be heated will be positioned.

Each burner is particularly constructed to fit it for use in the device, comprising the conduit 12 and the burner nozzle integral therewith and at right angles thereto. At the juncture of the two, air openings 13 are formed in the nozzle. Extending from the bore of the conduit 12 and through the side of the conduit, in axial alinement with the nozzle, isformed the fuel jet 14 through which a jet of fuel may be projected axially of the nozzle in which it is mixed with air drawn through the openings 18. The needle valve 15 is arranged at an angle to the con duit 12 to control the fuel jet 14:. The inclination being upwardly, the valve is'conveniently positioned for adjustment without increasing the lateral dimensions of the device. Beneath the end of the fuel conduit and the outer end of the nozzle is provided a pan 16, preferably formed of sheet metal, and bolted to the burner and the end of the furnace chamber. This pan serves to hold fluid fuel for starting purposes.

To the back of the furnace is secured the sheet metal guard or protector 17 which serves to protect the fuel tank from the heat of the furnace.

A furnace constructed as described is very compact and may be included Within comparatively small, overall dimensions, thus making it very suitable for prospectors use. Further, with the proportioning of the furnace chamber described and the arrangement of the burner nozzles very even and effective heating of the contents of the furnace is obtained.

What I claim as my invention is:

A portable furnace for heating tools com prising a closed furnace chamber of approximately equal height and breadth, of small cross-sectional area relative to its length and having a long opening in its front wall for the introduction of the articles to be heated above the level of the bottom of the chamher; and two burner nozzles for a fluid fuel extending through the opposite ends of the furnace chamber and directed towards one another, the said burners being arranged to discharge one slightly above and the other slightly below the axis of the furnace to effect even heating of tools positioned along the axis of the furnace.

Signed at Toronto this 23rd day of May, 1928.

ALEXANDER N. lYLioDONALl). 

